There is a technique called projection and mapping as a technique of projecting a desired content image onto a target object such as a building. Generally, since a target object has a three-dimensional shape, in a case where a content image is projected without being changed, the projected image appears to be distorted to a spectator at a position separate from a projection device due to unevenness of a surface of the target object or a difference between depths thereof. Thus, a correspondence between respective pixels of an imaging device and a projection device for each point of a target object is measured in advance, and a content image undergoes corresponding coordinate conversion so as to be projected, and thus a content image without distortion can be viewed.
In the related art, since a target object is a fixed object such as a building, typically, a correspondence between respective pixels of an imaging device and a projection device for each point of the target object is measured in advance, and projection and mapping are performed on the basis of correspondence information of the respective pixels of the fixed imaging device and projection device. However, there is the need to perform projection and mapping on a vehicle, a dancer, an athlete, or the like, and a device for preferably performing projection and mapping on a changing target object is desirable.
PTL 1 discloses a technique of mapping texture onto a surface of a target object of which a shape changes or which is moving, but does not take into consideration distortion of a projection image due to the three-dimensional target object. PTL 2 discloses a three-dimensional distance measurement device. PTL 3 discloses a measurement method using a rolling shutter type camera and a liquid crystal display type projector.
Here, when a device for performing projection and mapping on a moving object is considered, a delay time from the time of measurement to the time of video projection is considerably problematic. In a video projection device of 60 fps of the related art, since a time of 1/60 seconds or more is required in each imaging, transmission, computation, and display, a projection error of several tens of cm or more occurs even in slow movement of about 1 m per second, and thus projection onto a vehicle, a dancer, an athlete, and the like cannot be performed.
Here, in recent years, a display device called a digital mirror device (DMD) with a very high speed of over 1000 fps has been mounted on a projector available in the market. Therefore, if high-speed measurement can be performed at the same time with projection of a video according to any method without a viewer's awareness, such as using of such a high-speed device and a high-speed camera and also combining with invisible light, it is possible to perform projection and mapping on a moving object in real time.